Hydrogenated polybutadienes having a high vinyl content of from 85 to 100% are known from European Patent Application EP-A 0 024 315. The hydrogenated vinyl-polybutadienes described are distinguished by high ozone resistance but have the disadvantage that the elasticity of the products at lower temperatures leaves something to be desired owing to their relatively high glass transition temperatures and enthalpies of fusion.
Hydrogenated polybutadienes having a vinyl content of ≧20 wt. % and less than 40 wt. % and a degree of hydrogenation of 85 and above are also known from European Patent Application EP-A 1 258 498. The hydrogenated polymers described therein have a high degree of crystallization with good mechanical properties and good resistance to heat and weathering, but they have the disadvantage that their elasticity leaves something to be desired especially at low temperatures owing to their highly crystalline nature.
U.S. Pat. No. 4,025,478 discloses melt adhesive preparations based on hydrogenated vinyl-polybutadiene with a vinyl content from 50 to 95%, it is possible for the vinyl content to be adjusted to a double bond content of less than 15%, preferably less than 10%, by hydrogenation. In order to be suitable for the melt adhesive preparation, the hydrogenated vinyl-polybutadienes must have a Mooney viscosity of <10.
The effect of the Mooney viscosity is discussed in the examples of U.S. Pat. No. 4,025,478, specifically, Table 1 and Table 2, where a virtually completely hydrogenated vinyl-polybutadiene having a Mooney viscosity of 27 is used as comparison.
U.S. Pat. No. 3,959,161 describes lubricant compositions which possess inter alia as one component a small amount of a hydrogenated polybutadiene that has molecular weights in the range of from 20,000 to 300,000 and has a vinyl content of from 65 to 85%. The degree of hydrogenation of those products is from 75 to 100%. In order to be able to be effective as an additive in lubricant compositions and to be able to improve the viscosity index of those lubricant compositions, which consist substantially of lubricating oil, the hydrogenated vinyl-polybutadienes should have a particular molecular weight range, which is generally from 30,000 to 200,000. For the application of such hydrogenated polymers, for example in the manufacture of tires or tire components, such molecular weights, or the Mooney viscosities associated therewith, are too low to obtain tires or tire components having good physical properties.
U.S. Pat. No. 5,405,911 discloses hydrogenated polybutadienes which have a vinyl content of from 30 to 70% and, moreover, have terminal functional groups, such as hydroxyl groups. As a result of the terminal fictionalization, for example with hydroxyl groups, products having a comparatively low viscosity are obtained with the given vinyl contents and the given degree of hydrogenation of over 90%.
These products are suitable especially as coating compositions, sealing compositions and binders. An application for solid rubber molded bodies, e.g. for tires or tire components, is not described.
The object of the present invention was to provide hydrogenated poly-vinylbutadienes which are suitable for the production of solid molded bodies of any kind, especially for the production of tires and tire components, which have high resistance to oxygen and ozone and which have high elasticity at low temperatures. The hydrogenated poly-vinylbutadienes according to the present invention are also suitable for improving the impact resistance of thermoplastics when the latter are blended with the hydrogenated poly-vinylbutadienes according to the invention.